In the US speed limits are set by 85% of traffic speed on a road. So if the road was set for 30mph, and then you changed it to 20MPH with no other changes, you will immediately get 85% of drivers breaking the "limit."
Another way to say it is that UK's department for transport has incompetently designed 85% of their 20mph roads.
UK highways departments have had essentially zero budget for 2+ decades now. There's no funding to completely retrofit every single residential street to match the new signage. Most of them are already incredibly narrow and tight compared to your average North American street.
Hmm, sounds like the infrastructure for personal vehicles is pretty unsustainable, perhaps we should start closing off streets so that traffic will naturally be limited to locals only thus solving the problem from the demand side.
It ends up being kind of naive that drivers will simply respect a new, lower speed limit with no other changes. If the road could previousy accomodate a certain speed then some "arbitrary" sign won't change this.
But it can't accommodate that speed, people get injured and killed. Hence why they roll out the 20 zones. The average UK main road is like 1/3 the width of a North American residential cul-de-sac remember.
I think it's important to note that the US approach to speed limits is absolute fucking garbage and maybe one should be able to expect people piloting a vehicle to actually read and follow speed limits
@PowerCrazy@mondoman712
The 85% rule is insane. Basically, it means that speed limits are set by the most dangerous drivers.
The streets in my town were set out over 120 years ago. But as usual, cars have usurped the rights of prior users to the point where KSIs or peds and cyclists run at 4x the UK rate, and I don't even live in Florida. I mean, jaywalking laws were brought in to ease drivers' consciences about the number of pedestrians they were killing.
@PowerCrazy@mondoman712
Don't start me on public transit... 120 years ago my town had a fully-fledged tramway system which connected to other local systems spread over hundreds of miles centred on our local railway station.
The tracks were ripped up to provide space for parking...
Uh-oh! I got started!!!
I don't think you realise how old some roads are in the UK. They predate the concept of a department of transport by a long time, in cases like they can only work with what they have.
Designing a street so that people naturally drive a given speed is a pretty well-solved problem and you don't have to expand the surveillance state to do it. Also it usually makes the road more pleasant for everyone!
Cool create perverse incentives that do nothing to physically stop a car from barreling down a residential street, but also generate tax revenue so now the government is further discouraged from fixing the problem of a car barreling down a residential street, lest they lose revenue. Good job!